Very small input buffer (64KB) for creating LZ4 archive

[remittor]

7-Zip-zstd/C/zstdmt/lz4-mt_compress.c

Line 114 in a95e994

ctx->inputsize = 1024 * 64;

Recomended use 4MB input buffer.

[mcmilk]

I did some testing when this code was written, and increasing the buffer sizes there, resulted in speed drops. Thats the reason for this small buffer there.

[mcmilk]

Can you provide some benchmark which show that your recomended buffer size is better ?